The present technology relates to a position detection device, a position detection method, and an imaging apparatus, and more particularly, to a position detection device, a position detection method, and an imaging apparatus capable of detecting a position of a movable lens with high resolution and high accuracy by configuring the operation speed of a first detection sensor detecting an absolute position of the movable lens to be different from the operation speed of a second detection sensor detecting a relative position of the movable lens.
Various imaging apparatuses such as still cameras and video cameras are configured such that the position of a movable lens, such as a zoom lens, moved in an optical axis direction is detected and the driving of a lens group including the movable lens is controlled with high accuracy.
An example of the movable lens also includes a focus lens that has a focusing function. The focus lens has not only the function of focusing the image of a subject on an image sensor but also the function of a compensator that corrects a variation in an image surface when the zoom lens is moved.
In an imaging apparatus including an interchangeable lens that is detachably mounted on an apparatus body, a zoom ring is provided so that a manual operation can be performed on the interchangeable lens. When the zoom ring is rotated, the zoom lens is moved in an optical axis direction to perform a power changing operation.
As described above, the position of each movable lens in the optical axis direction is detected by a position detection device. The position detection device includes a first detection sensor that detects an absolute position of a movable lens and a second detection sensor that detects a relative position of the movable lens (for example, see Japanese Unexamined Patent Application Publication No. 2006-258586).
In an imaging apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2006-258586, a potentiometer that outputs a linear signal and has low accuracy is used as the first detection sensor and a magneto-resistive (MR) sensor that outputs a periodic signal and has high accuracy is used as the second detection sensor in order to detect the position of the zoom lens that is moved in the optical axis direction via a connection mechanism in response to the rotation of the zoom ring.